Joining metal sheet or strip

ABSTRACT

Apparatus for and method of joining the trailing and leading ends of a pair of metal sheet or strip sections, preferably in a continuous strip processing line, comprising a shear for trimming the ends of the sections, clamps for clamping the trimmed ends and holding them in narrow overlapped relation, planishing means to mash down the overlapped ends and welding means to weld the mashed-down ends, the clamps holding the overlapped ends against movement in a longitudinal direction away from each other after trimming and during planishing and welding operations.

United States Patent l Williams et al.

[ JOINING METAL SHEET OR STRIP [75] Inventors: Arthur L. Williams, Warren; Robert S. Ellis, Canfield, both of Ohio [73] Assignee: Wean United, lnc., Pittsburgh. Pa,

[22] Filed: Sept. 26, 1973 [2!] Appl. N0.: 400,856

Related US. Application Data [63] Continuation of Ser. No. 57,l59. July 22, i970,

abandoned.

[52] L8. Cl. 219/83 [5i] Int. Cl. 823K 11/06 [58] Field of Search H 219/82, 83

[56] References Cited UNITED STATES PATENTS 2.663.784 12/1953 lversen H t 2l9/83 Seeloff i. 219/83 3,313,9ll 4/l967 Sept. 30, 1975 3.5 lO,6Z5 5/[970 Wheeler 6! all. 2l9/83 Primary E.\'mniner l. V. Truhe Assisran! limminer-N. D. Herkamp Altorne Agent, or Firm-Michael Williams [5 7] ABSTRACT Apparatus for and method of joining the trailing and leading ends of a pair of metal sheet or strip sections, preferably in a Continuous strip processing line, comprising a shear for trimming the ends of the sections, clamps for clamping the trimmed ends and holding them in narrow overlapped relation planishing means to mash down the overlapped ends and welding means to weld the masheddown ends, the clamps holding the overlapped ends against movement in a longitudinal direction away from each other after trimming and during planishing and welding operations.

3 Claims, 5 Drawing Figures M wan... .s. m"...

JOINING METAL SHEET OR STRIP This application is a continuation of our prior application filed July 22, 1970, Ser. No. 57 159, and which is now abandoned.

BACKGROUND AND SUMMARY The joining of overlapped ends of metal sheets or strips is well known in the art. Such strip joining is usually accomplished in a continuous strip processing line where speed in joining is a major factor. Previous art known to applicants include welding apparatus wherein the strip ends are trimmed, and then worked on to pro' vide edges which are generally bevelled with respect to the plane of the sheet. This edge working has been accomplished as a separate operation, or has been performed by planishing rolls or peening hammers while the strips are narrowly overlapped.

Heretofore, insofar as we are aware, it has been considered necessary to slightly back off the planished edges to expose narrow widths of the faces thereof before welding the edges together, the theory being that the metal displaced in the welding operation will fill the spaces formed by backing off the planished edges.

We have discovered that it is unnecessary to back off the planished edges to provide a suitable weld substantially coplanar with the opposite faces of the sheets to be joined, and this has resulted in an increase of speed in the welding operation.

Accordingly, it is an object of our invention to pro vide new and improved methods of and apparatus for joining metal sheets and strip.

DESCRIPTION OF THE DRAWING In the drawing accompanying this description and forming a part of this specification, there is shown for purposes of illustration, an embodiment which our invention may assume, and in this drawing:

FIG. 1 is a schematic representation of a welding machine illustrating an embodiment of our invention,

FIG. 2 is a fragmentary, enlarged sectional view taken in the vicinity of the line 2-2 of FIG. 1,

FIGS. 3 and 4 are fragmentary, enlarged views of steps in the joining operation, and

FIG. 5 is a fragmentary view showing the joined sheets or strips.

DESCRIPTION OF PREFERRED EMBODIMENT The joining mechanism schematically shown in FIG. 1 comprises a base having rails or slide surfaces 11 along which a carriage 12 may reciprocate. A welder incorporating structure of the joining mechanism herein disclosed is shown in Taylor et al. U.S. Pat. No. 3,446,933, and FIG. 2 of the present drawing is similar to FIG. 12 of the drawings of said patent.

The carriage 12 is preferably of C-shape, as shown in FIG. I, having upper and lower legs 14,15, respectivcly,joined by a bight 16. The lower leg 15 may have rolls 17 which hold it to and guide it along the rails 11, and the upper leg may have rolls 18 which guide it along a fixed back-up rail 19 and support it against de- I'lection.

Mounted between the carriage legs 14,15, and adjacent to the bight 16, are upper and lower shear means 20,21, respectively, comprising upper and lower shear blades 22,23 (see FIG. 2) supported respectively by blade carriers 24,25. The metal strip S is shown as continuous in FIGS. I and 2 to indicate that it is moving through the throat of the C-shaped carriage for processing in a line downstream of the joining apparatus. Either one or both of the blade carriers 24,25 may be movable toward the strip by any suitable means (such as shown in the Taylor patent).

Clamp means 26,27 are disposed on opposite sides of the shear blades, as shown in FIG. 2, and each means comprises a pair of clamp arms 28,29. The clamp arms are shown in separated relation in FIG. 2 to permit the strip S to move freely therebetween in the direction of the arrow. The clamp means are carried by a stationary part of the joining apparatus, such as the frame (not shown) and may be operated in any suitable manner to accomplish functions as hereinafter described. As an example, the clamp means may be supported and operated as disclosed in the Taylor patent.

Just before the trailing end of the strip S moves through the throat of the carriage, strip movement is halted and clamps 28,29 of the clamp means 27 are tightly engaged against opposite sides of the trailing end of the strip. The shear blades 22,23 are brought together to crop a portion of the strip to insure a straight edge at the trailing end. The clamp means 27 are held clamped to the trailing end and are preferably moved out of the way to provide clearance for the leading end of an incoming strip. The clamps 28,29 of the clamp means 26 are then tightly clamped against opposite sides of the incoming strip and the shear blades are brought together to crop a portion of the incoming strip to insure a straight edge at the leading end which accurately matches the edge of the trailing end. The clamp means 26 are held clamped to the leading end and the clamp means are relatively moved in predetermined manner to provide a narrow overlap between the trailing strip end Ste and the leading strip end Stl, as shown in FIG. 3. All of the foregoing may be accomplished in a manner shown in the Taylor patent.

The overlapped strip ends are then subjected to sufficient compressive forces to cause the same to be mashed down to a condition wherein the ends are complementarily bevelled, as shown in FIG. 4. One way to apply the compressive force is to employ peening hammers extending from the carriage arms 14,15 toward the strip S, and cause such hammers to operate on the seam formed by the overlapped strips as the carriage I2 is moved from right to left in FIG. 1. However, it is presently preferred to employ a pair of planishing rolls 30,31 journalled in supports 32,33 extending from respective carriage legs 14,15. One or both supports 32,33 may incorporate means (such as well known fluid cylinders) to urge the rolls 30,31 toward the sheet 8 as the carriage 12 moves toward the latter.

In the present embodiment, the roll 31 is maintained so that its uppermost part is in the plane of the undersurface of the strip S and the top roll 30 is urged downwardly. Thus, as the carriage 12 is moved to the left, the rolls engage opposite faces of the overlapped strip ends, as seen in FIG. 3, and the roll 30 is forced toward the roll 31 with sufficient pressure to mash down the seam formed by the overlapped ends as the planishing rolls move along such seam from the right edge of the strip (with reference to FIG. 1) to the left.

Welding means is carried by the carriage 12 to weld the mashed-down seam immediately after the planishing rolls. As presently preferred, the welding means takes the form of a pair of seam welding wheels 35,36

journalled in supports 37,38 which are respectively carried by the carriage arms 14,15. As in the case of the planishing rolls, one or both welding wheels may be moved toward the strip S by suitable fluid cylinders, and preferably the lower weld wheel is maintained in line with the lower surface of the strip S while a fluid cylinder urges the upper weld wheel 35 toward the lower wheel so that opposite surfaces of the masheddown seam are engaged by the weld wheels while sufficient force and welding current is applied to the latter.

in operation, and assuming the strip ends have been trimmed and overlapped, the clamp means 26,27 re main clamped on the strip ends and their position remains unchanged while the planishing rolls 30,31 and the weld wheels 35,36 perform their function as the carriage 12 is moved from right to left. After the seam has been completely welded, the planishing rolls and weld wheels are separated so that the carriage 12 may move from left to right to be positioned for subsequent welding joining operation.

It has been found that by welding the mashed-down joint immediately following the planishing operation, the force of the weld wheels, and the heat generated in the welding operation, will produce a welded joint J (see FIG. 5) which does not materially extend beyond the opposite surfaces of the strip 5, despite the fact that the strip ends are firmly clamped against relative movement in a longitudinal direction away from each other at all times during the planishing and welding operations. Although FIGS. 3 and 4 show the clamps in different relative vertical relations, in actual practice there is no such shifting of the clamps since normally the strips to be joined are of a thickness of between 0.004 to 0.186 inches, and therefore FIGS. 3 and 4 are exaggerated only for purpose of disclosure.

We claim:

1. The method of welding adjacent leading and trailing ends of successive elongated sheet or strip workpieces of substantially equal end thicknesses comprising the steps of:

longitudinally shifting said workpieces to overlap the trailing end of one workpiece with the leading end of a successive workpiece,

fixedly clamping each said workpiece in position to prevent any relative movement thereof,

moving planishing means crosswise of said workpieces from one side edge to the other and while doing so progressively planishing said overlapped ends in transverse direction with sufficient force to cause the same to be mashed down to a condition wherein the overlapped ends are complementarily bevelled, and

moving welding means with and following said planishing means in the same crosswise movement, while the workpieces are held in initial clamped position without any longitudinal shifting thereof during or subsequent to the planishing step,

and causing said welding means, during said same crosswise movement and simultaneously with said planishing to transversely weld the planished leading and trailing ends under pressure to fuse the ends to each other in a joint not materially greater than the thickness of said workpieces thereadjacent.

2. The method according to claim I, wherein the planishing means and welding means are supported by a carriage for unitary movement crosswise of said workpieces,

said planishing means being in the form of a pair of cooperating rolls, one above the other and movable to closed position wherein they engage against opposite sides of said workpieces with planishing pressure, and to open position wherein they are clear of said opposite sides, and

said welding means being in the form of a pair of seam welding wheels, one above the other and movable to closed position wherein they engage against opposite sides of said workpieces with welding pressure, and to open position wherein they are clear of said opposite sides.

3. The method according to claim 2 wherein said carriage has a throat, and said planishing means and said welding means are mounted in said throat and with said carriage comprise a welding machine which forms part of a continuous, high-speed strip processing line wherein strip from one coil freely passes through said throat until the coil supply is substantially exhausted, the end portion of the strip on said coil forming said trailing end,

said processing line having a second coil, the start of which forms said leading end, the method further comprising interruption of movement of the strip through said throat when said trailing end approaches the latter, and threading said leading end of said second coil into said throat until said leading and trailing ends overlap,

moving said carriage from one position wherein said planishing means is spaced from one side edge of said workpieces in one direction cross-wise of said workpieces with said planishing rolls and welding wheels closed to successively and simultaneously planish and weld the overlap of said workpieces, movement of said carriage being continued to dis pose the same in another position wherein said welding means has completed the welding of said overlap and is spaced from the opposite side edge of said workpieces and said planishing rolls and welding wheels are open,

again starting movement of strip through said throat from the supply of said other coil,

and moving said carriage in an opposite direction to return it to said first position after strip movement has started, the open condition of said planishing and welding means providing clearance for strip movement. 

1. The method of welding adjacent leading and trailing ends of successive elongated sheet or strip workpieces of substantially equal end thicknesses comprising the steps of: longitudinally shifting said workpieces to overlap the trailing end of one workpiece with the leading end of a successive workpiece, fixedly clamping each said workpiece in position to prevent any relative movement thereof, moving planishing means crosswise of said workpieces from one side edge to the other and while doing so progressively planishing said overlapped ends in transverse direction with sufficient force to cause the same to be mashed down to a condition wherein the overlapped ends are complementarily bevelled, and moving welding means with and following said planishing means in the same crosswise movement, while the workpieces are held in initial clamped position without any longitudinal shifting thereof during or subsequent to the planishing step, and causing said welding means, during said same crosswise movement and simultaneously with said planishing to transversely weld the planished leading and trailing ends under pressure to fuse the ends to each other in a joint not materially greater than the thickness of said workpieces thereadjacent.
 2. The method according to claim 1, wherein the planishing means and welding means are supported by a carriage for unitary movement crosswise of said workpieces, said planishing means being in the form of a pair of cooperating rolls, one above the other and movable to closed position wherein they engage against opposite sides of said workpieces with planishing pressure, and to open position wherein they are clear of said opposite sides, and said welding means being in the form of a pair of seam welding wheels, one above the other and movable to closed position wherein they engage against opposite sides of said workpieces with welding pressure, and to open position wherein they are clear of said opposite sides.
 3. The method according to claim 2 wherein said carriage has a throat, and said planishing means and said welding means are mounted in said throat and with said carriage comprise a welding machine which forms part of a continuous, high-speed strip processing line wherein strip from one coil freely passes through said throat until the coil supply is substantially exhausted, the end Portion of the strip on said coil forming said trailing end, said processing line having a second coil, the start of which forms said leading end, the method further comprising interruption of movement of the strip through said throat when said trailing end approaches the latter, and threading said leading end of said second coil into said throat until said leading and trailing ends overlap, moving said carriage from one position wherein said planishing means is spaced from one side edge of said workpieces in one direction cross-wise of said workpieces with said planishing rolls and welding wheels closed to successively and simultaneously planish and weld the overlap of said workpieces, movement of said carriage being continued to dispose the same in another position wherein said welding means has completed the welding of said overlap and is spaced from the opposite side edge of said workpieces and said planishing rolls and welding wheels are open, again starting movement of strip through said throat from the supply of said other coil, and moving said carriage in an opposite direction to return it to said first position after strip movement has started, the open condition of said planishing and welding means providing clearance for strip movement. 